96% of the world's HIV infections are outside of North America. An HIV prevention research Center can be a resource to the field only if it has both a strong domestic scientific agenda and also vigorous Initiatives undertaken on a global scale in regions with high burden of HIV/AIDS. International HIV prevention research carries a number of important scientific and public health benefits. In an interconnected world, infectious diseases that arise in one region can come to dramatically influence the public health landscape on a global level. Such was the case for HIV infection. For reasons of humanitarism and also from the perspective of enlightened self-interest, it is neither ethical nor equitable for HIV prevention research initiatives to be limited to a single country while ignoring urgent needs elsewhere. From a scientific perspective, some research questions can best or can most feasibly be addressed through studies conducted abroad. This is especially true in regions with HIV epidemiology patterns, incidence, and prevalence rates that present unique opportunities to carry out studies abroad more effectively, definitely, quickly, and economically than would be possible in the domestic arena. Finally, lessons learned and findings discovered in international research can Inform and benefit public health HIV prevention efforts in the United States. CAIR's International Core became a part of the Center's structure In 2004, ten years into the life of the Center. The Core's objective was to stimulate and facilitate research initiatives, especially in Russia, in other countries of the former Soviet Union, and in emerging post-socialist democracies in Eastern Europe. This region has been a main focus of CAIR's work because It has one of the world's newest, most rapidly increasing, but scientifically neglected HIV epidemics; because the epidemic's trajectory is so closely linked to massive cultural, social, and behavioral changes since the breakup of the Soviet Union, all of which are areas of CAIR expertise; and because of unique scientific opportunities in the region. The International Core's research stimulation and support aims have been successfully achieved. CAIR investigators have been awarded 12 extramural research grants and published over 50 articles calling scientific attention to the region's needs, some reporting on outcomes of successful HIV prevention intervention trials undertaken by CAIR investigators. The Core has facilitated these accomplishments. In addition, CAIR's International Core is a resource that links our Center's investigators with research and agency partners abroad; provides research training to both U.S. and host country teams; trains Fellows from the United States and in host countries in HIV prevention research skills; and serves as a resource to scientists, organizations, and institutions abroad. During the renewal period, the International Core will continue and will expand Its scientific, training, and research support services. A large proportion of CAIR's international research continues to Involve studies undertaken in Eastern Europe. Because many studies are being carried out in the same region, they share similar research support needs. Rather than require each study and each investigator to individually arrange ways to meet these needs, the Core reduces research redundancy and cost?and increases research efficiency?by providing centralized resources that meet multiple projects' needs. This is especially the case for areas of shared project need such as Russian-English translation, interpretation, and cultural consultation, where the Core has experience and specialized resources that can be utilized by multiple studies. Because we foresee an expansion of international research in the area of combination biomedical, behavioral, and social HIV prevention intervention, the Core has added for the renewal period the scientific expertise of leading authorities from the post-Soviet region in the field of antiretroviral medication uptake and adherence. Their expertise will benefit CAIR investigators initiating research that involves combination behavioral/biomedical prevention. While many of the Core's resources remain focused on Eastern Europe, the Core will expand some key functions in the renewal period to support CAIR researchers who are planning or are conducting international studies in other regions.